Described below is a measuring device for determining temperature and/or pressure, with at least one transmission/reception unit for ultrasonic pulses and with at least one means for the reflection of ultrasonic pulses, and a method for operating the measuring device and to a use of the measuring device.
Turbomachines, such as, for example, steam or gas turbines, are used as thermal engines in industry in order to transfer an energy stored in a gas stream into a mechanical energy, in particular into a rotational movement. Furthermore, turbomachines, such as compressors, come under consideration, by which mechanical energy can be supplied to a gas stream. In order in gas turbines to achieve as high an overall efficiency as possible in terms of energy utilization, the gas inlet temperatures from the combustion chamber into the flow duct of the gas turbine are selected as high as possible. For example, the gas inlet temperatures lie above 1000° C.
This makes it necessary, under these high physical loads, for the turbomachine to be kept under observation during operation. In this case, in particular, the temperature and pressure measurement within the turbomachine delivers important information on the state of the turbomachine. For this purpose, as a rule, measuring probes mounted in the turbomachine are used, the signal and supply lines of which lead outward through the wall of the turbomachine by leadthroughs. A large number of temperature and pressure measurement points therefore requires a large number of leadthroughs and seals. Under the high physical loads, these always constitute error sources which are as far as possible to be avoided, in order to ensure that the turbomachine operates reliably.